The invention relates to completion of wells including completing a well with plural fluid flow paths, such as paths for concurrent injection and production of well fluids.
A completion string positioned in a well to produce fluids from one or more downhole formation zones may include casing, production tubing, packers, valves, pumps, and other components. One or more well sections may be perforated using a perforating gun string to create openings in the casing and to extend perforations into one or more corresponding formation zones. Fluid flows from the one or more formation zones through the perforations and casing openings into the wellbore and up the production tubing to the surface.
In some wells, simultaneous production and injection may be employed for a number of reasons. For example, it may be desirable to inject fluid into a first zone to increase reservoir pressure in a second zone to enhance the productivity of the second zone reservoir. Conventionally, simultaneous production and injection may be accomplished with a cross-flow packer that provides two flow paths, one for production and one for injection. The cross-flow packer isolates two sections of the wellbore, an upper section above the packer and a lower section below the packer. In the upper section, injection fluid may be pumped through the annular cavity between the outer wall of the production tubing and the inner wall of the casing, and production fluid is produced through the inner bore of the tubing. The cross-over packer allows the two fluid flows (one for injection and the other for production) to "cross over" at the packer between the tubing-casing annular cavity and the tubing inner bore.
However, use of conventional cross-flow packers may be associated with several limitations. Shut-off of the cross-over ports in the cross-over packer may not be available. As a result, cross-flow of fluids between the injection and production zones may occur during intervention, completion, and work-over operations. In addition, to perform operations in which access below the cross-over packer is needed, the cross-over packer may have to be milled to gain access. Furthermore, flow areas through the cross-over packer for injection and production fluid flows may be limited.
A need thus exists for improved equipment that provides multiple fluid paths, including cross-over paths.